How to check a trapezoidal steel sheet quotation before ordering

The quotation should include the selected profile’s full designation. Different T18 sheets have different cross-sections; example cover widths include 1128 and 1100 mm. These sheets must not be treated as identical. The difference affects the cutting plan, number of sheet runs and matching details. An additional order also needs the edge geometry to match.

Specify whether the sheet is for a roof or façade and check which side has the decorative finish. For an extension, establish compatibility with the older material. If a substitute is proposed, obtain its data sheet before acceptance. “Same colour and height” is not enough.

Pay attention to roof and wall variant designations. The decorative coating may be on a different side of the profile. In an existing covering, that difference also affects connection to neighbouring sheets. Examining a sample is then more useful than a general assurance of a similar shape.

Thickness, steel grade and profile must match the structural assumptions. Support spacing and width also matter. Manufacturers’ tables use different structural arrangements; do not select convenient figures from several incompatible tables for one roof.

If the designer specified a particular version, ask them to review any proposed change. Saying that the replacement is roughly the same is insufficient. Also check minimum pitch and overlaps. Load capacity and weather-tightness are separate requirements: satisfying one does not confirm the other.

The offer should state quantities and lengths, and identify which area the total represents. Overall dimensions do not equal effective cover area. On simple roof slopes, the number of sheet runs can be checked by dividing the roof width by the cover width and rounding up.

Valleys and diagonal edges need a cutting drawing. Ask which offcuts can be reused. Do not assume an arbitrary waste percentage unrelated to the roof geometry. Confirm that lengths include the designed edge details. Ordering extra “just in case” can create unnecessary cost and difficult site cutting.

If sheets exceed transport capabilities, agree how to divide them before production. Cutting them later on site changes the joint detail and may require a support, overlap and seal. Shortening a sheet is therefore more than a logistics decision.

Prices may be per gross m², effective m² or linear metre, with extras charged separately. A free quote should give a clear unit for every item. Separate the sheet, anti-condensation fleece, protective film and accessories. Only then can two offers be compared without counting the same cost twice.

Check flashings at the eaves, verges, ridge and chimney, and include seals and required fixings. Pay attention to transport and unloading. Small orders may incur different logistics charges. Without these items, two quotations may look comparable only on their first page.

Before buying, obtain the product data sheet, the appropriate declaration of performance and installation instructions. Clarify warranty conditions and retain the order confirmation and batch identification. The purpose is not to collect paperwork for its own sake, but to identify the material and its intended use.

At delivery, check package count, lengths and surface condition, especially corners and edges. Document damage before moving sheets where possible. Agree safe unloading and storage arrangements. Incorrect handling can deform material even when it arrived in good condition.

The installation team should know the model, instructions and required accessories. Establish who checks the supporting substrate and adapts flashings. Arrange inspection before important joints are concealed. Photographs of details help assess any subsequent defect.

After installation, remove swarf and inspect the coating. The roof also needs later inspections, cleaning and checks of flashings. Plan access to valleys and chimney surroundings. The purchase then ends with a maintenance plan rather than merely payment for delivery. Maintenance conditions should be known before choosing the covering.

Use the product name from the seller’s offer in your enquiry to the installer. This reduces the risk of pricing installation for another format or assuming unsuitable accessories. Both quotations should describe the same roof.

No. Product documentation does not replace checks of the design, supports, loads and details.

Not automatically. A change can affect load capacity, coverage and accessory compatibility.